This invention relates to a multi-mode reproducing apparatus preferably of the electrostatographic type. The apparatus includes means for copying documents selectively at one of a plurality of magnifications.
An optical system is provided which is arranged to stripwise scan a stationary document in one mode of operation or to be beld fixed at a given position to stripwise view a moving document. Reduction copying is accomplished in this latter mode of operation. In order to accomplish reduction copying an optical element not part of the stripwise scanning system is inserted into the optical path of the optical system fixed at the given position. In accordance with this invention an apparatus is provided for preventing a premature rearrangement of the optical system before the added optical element has been removed from the optical path.
A variety of electrostatographic reproducing machines are commercially employed which have different modes of operation. One type of machine utilizes a moving original exposure system wherein an original document is moved past a fixed slit optical system for projecting an image onto the moving photoconductive surface. These machines include a means for changing the magnification of the projected image to provide reduction copies. Exemplary of patents in this area is U.S. Pat. Nos. 3,076,392, to Cerasani et al., and 3,649,114 to Vlach et al.
Other machines have been adapted to copy stationary original documents at a variety of magnifications or reductions through the use of a scanning optical system. Exemplary of patents in this area are U.S. Pat. Nos. 3,476,478, to Rees, Jr.; 3,542,467 to Furgeson; 3,614,222 to Post; and 3,837,743 to Amemiya. Another approach which has been utilized for projecting images for reproduction at varying magnifications from a stationary original comprises full frame exposure. Exemplary of patents in this area are U.S. Pat Nos. 3,543,289 to Koizumi; 3,687,544 to Muller; 3,703,334 to Knechtel; and German Offenlegungsschrift 2,154,944 to Libby.
U.S. Pat. Nos. 3,703,334 to Knechtel and 3,837,743 to Amemiya set forth above are also significant in that they disclose the use of a separate reflector or add reflectors, respectively, which are selectively positionable in the optical path for changing the conjugate distance of the optical system for providing varying magnifications.
The aforenoted machines are adapted to provide one or more modes of copying having different magnifications. In the optical systems of these machines, some means is usually provided for changing the conjugate relationship on the object and image sides of the projection lens. This may be accomplished by translating the lens between different positions for different projected image magnifications or in accordance with an alternative approach by utilizing more than one lens whereby different lenses are selectively positionable in the optical path, depending upon the projected image magnification desired. See, for example, U.S. Pat. No. 3,779,642 to Ogawa.
Other forms of multi-mode copiers are available commercially. For example, in the Xerox 3100 LDC machine an optical system is provided which enables the machine to copy from a stationary original in a first scanning mode or from a moving original in a second fixed optical mode. This latter mode is particularly adapted for copying documents larger than the conventional viewing platen size. U.S. Pat. No. 3,900,258 to Hoppner et al. [1] is illustrative of a machine similar in many respects to the 3100 LDC machine.
Reproducing apparatuses including the capability of making copies from both moving and stationary originals are also described in U.S. Pat. No. 3,833,296 to Vola, and in IBM Technical Disclosure Bulletin, Vol. 12, No. 1, at page 173, June 1969.
It has been found desirable, to provide a multi-mode reproducing apparatus having various unique features of the 3100 LDC machine, including its extremely compact size, but also having the capability of reduction copying.
One approach to such a machine is described in U.S. application Ser. No. 588,971, filed June 20, 1975 now U.S. Pat. No. 4,027,963, to Hoppner et al. [2]. In that application a multi-mode reproducing apparatus is provided including both moving and stationary original exposure modes, with at least two modes of moving original exposure at differing copy image magnifications. The Hoppner et al. [2] machine includes a first optical mode wherein a stationary document is viewed and an image thereof is projected onto a moving imaging surface. In a second mode a document moving at a first speed synchronized to the speed of the moving imaging surface is viewed and an image thereof projected onto the imaging surface at a desired magnification. In a third mode a document moving at a second speed synchronized to the speed of the moving imaging surface is viewed and an image thereof projected onto the surface at a reduced magnification. In the reduction mode of operation a scanning optical system is held fixed at a given position and an additional optical element comprising an add mirror is inserted into the optical path in order to change the conjugate on the object side of the lens. The lens is also shifted to a new position to align it with a repositioned optical path.
A variety of devices are known in the prior art for interlocking various functions of a reproducing machine. For example, interlock switches are utilized in conjunction with the covers of the machine to shutdown machine operation upon opening of the covers. A variety of failsafe mechanisms are found in the prior art which allow a machine to continue to complete a copying cycle even though the control system has received a premature mode changing signal.
The use of selectively added optical elements causes problems in changing modes of operation. Optical mode changing usually necessitates rearranging various of the optical elements. In the highly compact machine of this invention a prioritization of the mode changing movements of the optical elements is provided to prevent one element from crashing into another or otherwise interferring with its movement.